Some of people in the swamp in holding a vigil for Captain Jack may seem bit odd unless you remember something from Jack's backstory: the reason he was branded a pirate was because he freed a group of slaves. The people in the swamps could very well be the slaves he freed and they're paying their respects to the person that saved them.
Let's be honest: Davy Jones' pet kraken doesn't look all that much like a kraken is supposed to, basically a scaled-up squid or octopus, which would include a beak like those cephalopods have rather than a circular maw of sharp teeth. However, there is a mythical/folkloric cephalopod that does have a mouth like that: the lusca, which, coincidentally, is from the Caribbean!
Tia Dalma's story about Davy Jones falling in love with the sea or a woman is full of foreshadowing once you realize that she is the sea goddess Calypso bound in human form.
Jack reacting relatively calmly to Bootstrap Bill appearing on his ship makes sense when you realise that a) he's seen and even temporarily experienced the effects of an undead curse before, b) he's also, at some point, met Davy Jones, cthulhuoid captain of The Flying Dutchman and c) unlike Barbossa, he doesn't have any particular enmity with Bill, meaning he has little reason to fear attack.
Upon rewatch, there are several hints of Barbossa’s resurrection in the first scene in Tia Dalma’s hut. Jack the monkey seems to be very interested in the corpse behind the curtain and human Jack can be seen idly holding Barbossa’s hat.
As stated on the Curse Fridge Page, the reveal of Jack's backstory with Davy Jones retroactively explains a key unanswered question from the first film: Why was Jack seeking the Isla de Muerta and the Aztec Gold in the first place? Barbossa and the rest of the Black Pearl crew had all heard the tales of the cursed Aztec Gold and initially dismissed them as superstitious nonsense. But Jack was already 2 years into his deal with Jones at that point and knew the clock was ticking. Jack was probably gambling that if the stories were true, the Aztec Gold might potentially somehow cancel or invalidate his debt to Jones.
The Deal also adds additional context to Jack's desire for revenge on Barbossa. By mutinying and stealing the Pearl, Barbossa unwittingly made Jack's deal with Jones — the very thing he'd sold his soul for — worthless. Jack wasted the next decade on chasing and trying to recover the Pearl instead of looking for means of escaping the debt — and by the time he succeeded, there was now only one year left on the clock.
Elizabeth fainting and the three guys ignoring her is Played for Laughs. But think about it—that same move in Curse of the Black Peal would have almost certainly have worked. Norrington and Will both care for her, and Jack seems to have a compulsion to help in situations like that. The fact that it didn't work shows just how much the men have become obsessed with the Heart of Davy Jones, offering some nice foreshadowing as to their roles in the third film: Will would lose Elizabeth for his father, Norrington would lose Elizabeth to get his job, and Jack has become more self-centered than normal.
On the other hand, it's not very believable- it's a suspiciously convenient time, she's done it before, and they must all realise that she's not even wearing any corsets!
She could have fainted from low blood sugar/the heat.
IIRC, before "fainting" Elizabeth dramatically cries out "Oh! The heat!"
They probably did not even see her fainting, each being busy fighting two opponents...
Alternately, they each knew her well enough personally now that they simply didn't buy it. Will's a friend from childhood who was at point engaged to her, Jack's been hanging out with her on a pirate ship (as well as an equally hot and brutal island the movie before), and Norrington's seen her faint once for real (in the first movie due to a suffocating corset) and he's seen that trick before (when Jack was about to be hanged).
After you've seen "Dead Man's Chest", now you know the basic tactic of Kraken (grab the hull, kill the crew with tentacles, drag the ship underwater). You realize (just as Will probably did, and later Jack too) that when Will stepped on what he believed was the Dutchman, the Kraken was just feet under him, still holding the hull and... playing with the corpses, momentarily calm and waiting just some feet away.
While searching for Jack in the beginning, Will ends up talking to a trader that says that he trades with the Pelegostos for long pork. More knowledgeable viewers might recognize that as another term for human meat. Even if the trader himself wasn't a cannibal (which in itself is very likely since he called it "delicious"), he's still been selling human meat to unaware customers.
I always interpreted it as the other way around; the trader sells people (dead or alive) to the Pelegostos in exchange for something else. Not that that's any better, mind you...
That island also has tins of spice marked with the insignia for the EITC, which Jack dwells on for a moment. The one Jack grabs in particular appears to contain paprika, which grows fairly well in the tropical climate of the Caribbean islands. Make of that what you will.
The man states he trades specifically spices for "long pork." Whether he knows what the euphemism means or not, he's still eaten, and possibly sold or traded to others, human meat.
